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Breithaupt Pilot Balloon Theodolites
http://www.breithaupt.de/theod.htm

F. W. Breithaupt & Sohn GmbH & Co. Kassel Germany, was founded in 1762 and is still a family owned enterprise in the seventh generation.  Breithaupt pilot balloon theodolites are in use in about 40 countries worldwide.  The company also manufactures Leveling Instruments, Theodolites, Topographical Instruments, Compasses, and Geodetic Testing Instruments.

Photo of TEBAL (Garat looks similar but without cable in lower right)

tebal.jpg (16783 bytes)
1  Open sights
2  Illumination of Reticule
3  Eyepiece of the telescope
4  Vertical circle
5  Vernier for vertical
6  Illumination of Circles
7  Vernier for horizontal
8  Horizontal circle
9  Knurled ring for horizontal
10  Clamping plate
11  Base plate
12 Cable Connection (tebal)
13  User supplied RS232 computer or logging device (not shown)
14  Leveling screw
15  Wormdrive for lateral movement
16  Tubular level
17  Tubular compass TEROB

The Garat and Tebal are very similar units with the later having an RS232 data output.   They may be ordered with a compass for alignment, 16 or 20x scopes, eyepiece filters and a wide angle finder scope.  An electronic signal clock (60 second time signals with warning signal) is available.  Theodolites utilize a tribrach mounting system.  The open site is also a "bent axis" system which allows the user to rough site from the same position as when sighting through the telescope.  The telescopes use coated optics with 48mm objectives for bright images.

The circles of these units are graduated in 1 degree intervals with vernier reading to .1 degree.  The vertical and horizontal circle verniers are placed directly vertical to assist in taking reading quickly.  The telescope utilizes a 48mm objective for a bright image and is fixed focus at infinity.  There is no digital display directly mounted on the Tebal.  The Tebal directly supports RS232 output of measurements for use with a user supplied data logging or computing set up.

Both theodolites have Illuminated reticules and circles.